10-YEAR-OLD girl in Canada has become the youngest person to discover a supernova - an exploding star which can briefly outshine a whole galaxy. Kathryn Gray was studying images taken at an amateur observatory which had been sent to her father. She spotted the magnitude 17 supernova on Sunday. Supernovas - which are rare events - are stellar explosions that mark the violent deaths of stars several times bigger than the Sun. The supernova was discovered in the galaxy UGC 3378, about 240 million light years away, in the constellation of Camelopardalis. Im really excited. It feels really good, Ms Gray told Canadas Star newspaper. Age estimate Kathryns father, Paul Gray, himself an amateur astronomer, helped her make the discovery by taking the steps to rule out asteroids and checking the list of current known supernovas. The discovery was then verified by independent astronomer and officially registered, the Royal Astronomical Society of Canada (RASC) said in a statement. BBC